The Alphabet-owned company, which was put up for sale in mid-March, specialised in making robots for the military before it was bought in 2013.

Last year Google was awarded a patent for a system that would enable the user to allocate tasks to "a plurality of robotic devices" via the cloud, giving rise to speculation that the company is building a robot army.

In a patent registered with the United States Patent and Trademark Office, Google describes how a "computing component" (such as a PC or mobile phone) could communicate with robots over a network to allocate tasks and receive information.